User manual

Section 12: Status Model Series 3700 System Switch/Multimeter Reference Manual
12-2 3700S-901-01 Rev. C / July 2008
Negative and positive transition registers
Negative-transition register (NTR): When a bit in an NTR is set by the
user, the corresponding bit in the event register will set when the
corresponding bit in the condition register transitions from 1 to 0.
Positive-transition register (PTR): When a bit in a PTR is set by the user,
the corresponding bit in the event register will set when the corresponding
bit in the condition register transitions from 0 to 1.
Status byte and SRQ
The status byte register receives the summary bits of the five status register
sets, a master summary bit, and two queues. The register sets and queues
monitor the various instrument events. When an enabled event occurs, it sets a
summary bit in the status byte register. When a summary bit of the status byte is
set and its corresponding enable bit is set (as programmed by the user), the
RQS/MSS bit will set to indicate that an SRQ has occurred, and the GPIB SRQ
line will be asserted.
Figure 12-1: Status byte and queues
Queues
The Series 3700 uses an output queue and an error queue. The response
messages, such as requested readings, are placed in the output queue. As
various programming errors and status messages occur, they are placed in the
error queue. When a queue contains data, it sets the appropriate summary bit of
the status byte register (EAV for the error queue; MAV for the output queue).